1. Field of the Invention
The present invention relates generally to water cooling tower systems, and more particularly to a water level monitoring system for use with a water cooling towers and the like wherein the water level monitoring system controls the supply of make-up water to the reservoir of the water cooling tower.
2. Description of the Prior Art
Many different types of water cooling tower systems are known in the art. Similarly, many different types of heat exchangers, blowers, fans and the like are conventionally used in conjunction with such water cooling tower systems. Regardless of the particular construction of a specific water cooling tower, all have at least one thing in common.
All water cooling tower systems contain some type of reservoir or basin located in the bottom thereof for collecting the recirculated water. Since the recirculated water diminishes on each cycle due to the evaporation of the water which is responsible for the cooling action, additional make-up water must be added. The prior art uses various schemes for adding make-up water from a supply of water to the basin or reservoir of the cooling tower to compensate for the water lost in the evaporation process.
Relatively few of the prior attempts have used a float-type device and those that have, have encountered a relatively severe problem. If the reservoir is chosen to have a predetermined desired level of water in it at all times for maximum operating efficiency, a float can be used to determine when the water level has risen above or fallen below the predetermined desired water level. However, typical float mechanisms will tend to oscillate around the predetermined desired water level continually trying to add and then stop the supply of make-up water to the reservoir each time the sensor detects the water level on one side or the other. This causes maintenance problems, valve wear, system failure and the like. Some systems may attempt to use a float which trips a first switch when it rises to a level above the predetermined level of water and another switch when it falls a predetermined distance below. However, such systems tend to deteriorate quickly with time, mineral deposits on the switches, and the like. Further, however, the problem is actually doubled rather than solved since now the oscillation tends to take place on both sides of the upper and lower limit switches.
The present invention solves these problems of the prior art by providing an equivalent of a delay or an additional amount of force required to trip a trigger mechanism from a first position to a second position which is equivalent to the float having to rise a first predetermined distance above the predetermined desired water level or fall a second predetermined distance below the predetermined desired water level. In this manner, all oscillations are eliminated and a highly accurate indication of the actual water level can be made and used for control purposes.